The present invention is generally related to electrical scanning and imaging technology and, more particularly, is related to a system and method for scanning documents into electrical format using contact image sensors.
Current scanning technology now facilitates scanning of color documents and the like to create a digital document therefrom. The digital document may then be displayed on an appropriate display device such as a cathode ray tube (CRT), etc. Computer systems provide significant flexibility to users to manipulate or change a digital document in a myriad of ways.
In order to generate the digital document from a hardcopy document, sensors are generally employed in conjunction with a number of colored lights. A hardcopy document is typically run through a scanner at a slow speed while the scanner acquires a dense pattern of sensor spots from the document by manipulating the colored lights and sampling values on the sensors. To acquire full color digital images, each of the sensor spots is preferably sampled multiple times, each time the sensor spot being exposed to light of a different color. The color of the lights used may be, for example, red, blue, and green.
The sensors employed are quite dense, even up to 600 sensors per inch. Thus, it takes a significant amount of time to sense each color for each sensor spot on the scan target as there is a significant amount of data created that must be processed and stored.
In light of the foregoing, the present invention provides a system in a scanner for acquiring a number of sensor spots to create a digital image therefrom and an accompanying method. In one embodiment, the system comprises a plurality of light sources positioned to project an amount of light at a scan target. The light sources are preferably red, blue, and green. The system also includes a contact image sensor positioned to receive an amount of reflected light from the scan target. According to an embodiment of the present invention, the contact image sensor includes a number of sensors arranged in a nonlinear pattern. The scan target is moved relative to the contact image sensor or vice versa during the scan operation using suitable apparatus. The light sources are alternatively illuminated to obtain sensor spots from the scan target via the sensors. The sensor spots are stored in memory, and an image is generated therefrom.
The present invention also provides a method for acquiring a number of sensor spots from a scan target to create a digital image. Broadly defined, the method comprises the steps of: projecting an amount of light from one of a number of light sources at a scan target; and receiving an amount of reflected light from the scan target in a contact image sensor having a number of sensors arranged in a nonlinear pattern.
The contact image sensor of the present invention with the nonlinear pattern of sensors provides a distinct advantage in that a color artifact associated with the use of linear sensors is substantially reduced or eliminated.